Something Else I Was Wrong About

A point that I've seen brought up many times this off season is that we should rid ourselves of Jeff Kent and replace him with Tony Abreu. My first instinct was a simple, "that's a really dumb idea". Our team is hurting for offense and replacing possibly one of our best hitters with a guy that can on base .310 is not something that seems like a good idea.  However, after going through this years PECOTA projections, I started to reconsider and decided to seriously look at whether or not we can replace Jeff Kent's production right now with Tony Abreu.

The first thing to consider is offense, where Jeff Kent has his huge advantage over Abreu. Using this years PECOTA projections, we can figure out the projected difference between the bats of Kent and Abreu. Kent is projected to have a 32.1 VORP in 443 plate appearances, while Abreu looks to have a 12.5 VORP in 469 plate appearances. If you normalize both players to the same 443 plate apparances, Abreu's VORP drops to 11.8, so if Kent and Abreu both receive equal play time, Kent has a 20.3 run advantage over Abreu offensively.

Where Abreu can make up the difference is defense. It could be argued a few years ago that Kent was underrated defensively. When he originally came to LA and people complained that breaking up the Cora/Izturis middle infield was suicidal, it could actually be argued that Kent was a better defender than Cora in 2004. Kent had both a higher zone rating and a better rate2 than Cora that year.  He didn't have much range but he was great at positioning and was excellent at turning the double play. Now though, that's pretty much gone. Not much range has turned into no range as Kent ranked as the fourth worst second baseman in baseball according to John Dewan's + - system, and watching Kent made it clear that he just couldn't handle anything that wasn't hit right next to him. So, how good does Tony Abreu have to be defensively to make up for his bat?

To measure this, we first have to figure out how much a play made by a second baseman is worth, since + - is measured in plays. Fortunately, this is very doable for a middle infielder, since it's hard to imagine any play that a second baseman misses will turn into anything but a single.  Because of this, we can assume the value of any missed play is the difference between a single, and an out. According to linear weights a single is worth .465 runs and an out is worth -.25 runs, so a missed play by a second baseman costs the team .715 runs on average. This gets worse once we factor in double plays. Since there's no authoritative source on double play opportunities we have to estimate how many balls a second baseman fields are double play balls. NL second basemen had 7,161 assists last year, and they turned 1,774 double plays. If we assume that a second baseman fielded half of those double plays, we can make the figure that one in every eight balls a second baseman fields is a double play ball. Since a double play is worth -.839 runs, missing a double play ball costs your team 1.304 runs. With these two numbers in hand, the average missed play by second baseman costs a team .789 runs.

If we assume that Kent's defense degrades a bit as he hits 40, he'll be worth about -15 plays this year. This means that over the course of the year, Jeff Kent's glove will cost the Dodgers 11.835 runs versus the average second baseman. If you subtract these runs from his projected VORP, Jeff Kent will be worth 20.27 runs this year. (This isn't actually true since VORP is against replacement level and + - is against the average, but since I'm using the same system for both players, this works.)

With Abreu's adjusted VORP of 11.8, Abreu would have to put up a defensive rating of +11 in order match Kent's production. This is a good number, but not impossible to obtain. If Abreu did that in 2007, he would be the 7th best second baseman in baseball, around Brandon Phillips and Kaz Matsui. If the scouting reports on Abreu's defense are true, then this is definitely doable.

When you consider the odds of Jeff Kent simply falling off a cliff when he hits 40, then maybe it would be a good idea to trade Kent now and replace him with Abreu. Abreu's PECOTA projection of .279/.326/.408 seems within his reach, and simply having an above average glove will cause his value to eclipse Kent's. However, the Dodgers offense is fragile enough where it would take serious stones to weaken it further to improve on the team defense. On paper, replacing Kent with the arguably superior player and getting something back in a trade is a brilliant thing to do, but there's so much risk involved that I couldn't see a team that's trying to win this year attempting it.